Saturday, December 22, 2018

It’s not often that an island disappears off the map, but that’s just
what happened in October 2018.
A remote but ecologically important
island was lost to the sea in the wake of one of the most intense
hurricanes on record for the North Pacific.

Around October 3, Hurricane Walaka
passed the Hawaiian Islands, including an archipelago about 900
kilometers (550 miles) northwest of Honolulu known as the
Papahānaumokuākea Marine National Monument.
Strong surges from Walaka
inundated the shallow islets, one of which has been almost completely
reclaimed by the ocean.

The Operational Land Imager
on Landsat 8 captured these natural-color images of East Island on
September 11 (left) and October 13, 2018 (right).
The storm washed away
the 11-acre strip of sand and gravel, and only two slivers of land have
re-emerged since the hurricane struck.
Storm surges also deposited sand
and debris across Tern Island, which is northwest of East Island.

East Island is part of the French Frigate Shoals, one of the most
significant coral reef systems in Papahānaumokuākea.
The archipelago
formed millions of years ago when a deep-sea “hotspot”
created underwater volcanoes, which eventually rose to the ocean’s
surface to became islands.

While East Island was uninhabited by people,
it provided nesting grounds for the threatened Hawaiian green sea
turtles and pupping grounds for endangered monk seals, of which there
are only 1,400 in the world.
Scientists believe many of the animals had already left the island
before the hurricane hit because it was the end of turtle and seal
breeding season.
However, unhatched turtle nests were likely affected.
Researchers must wait until next year to return to the islets for a more
extensive survey of the impact on wildlife.

In the meantime, a marine debris team
worked within the Monument zone in early November to remove more than
160,000 pounds of lost or abandoned fishing nets and plastic that could
endanger marine animals.

East Island is not the first island to disappear from the French
Frigate Shoals.
Whale-Skate Islet was lost to erosion in the 1990s,
while Trig Island eroded earlier in 2018—a common occurrence in
sand-dominated ecosystems.
Scientists believe the mammals adapted to the
ecosystem changes at Whale-Skate and Trig by finding new breeding
locations, so they expect the same to happen now that East Island is
gone.